The hardcore 'structural / materialist'
filmmaking that characterised much of the work produced at the
LFMC in the early 1970s can be very challenging for the
viewer.

Anyone wandering in from the street, with the expectations of commercial (they used to call it "dominant") cinema would not understand these films at all. Not only is there no narrative, but there's most likely no people, no sound, no editing and sometimes no discernible imagery at all.

'Structural Film' was a genre defined by the American critic P. Adams Sitney in 1967. In the late 1960s it became the dominant form of new experimental film. Films made in the US by Hollis Frampton, George Landow, Michael Snow and others often took the form of intellectual exercises, in which the viewer would inevitably try to work out the scheme or idea behind the film's construction. The British work was much more loosely contrived, and really concerned with the raw physicality of the film medium and the inherent properties of the celluloid strip.